1-[4-(5-Cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine, its physiologically acceptable salts thereof (U.S. Pat. No. 5,532,241, column 7, lines 30 to 58), a process (U.S. Pat. No. 5,532,241, Example 4) by which it/they can be prepared and their use in treating certain medical disorders are known from U.S. Pat. No. 5,532,241 and WO 00/72832.
Example 4 of U.S. Pat. No. 5,532,241 describes the preparation of 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride by reacting 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carboxybenzofuran-5-yl)piperazine at first with 2-chloro-1-methylpyridinium methanesulfonate in N-methylpyrrolidine and then with dried NH3.
Customary working up gives the free base 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carboxybenzofuran-5-yl)piperazine. 700 mg of the base are dissolved in 30 ml 2-propanol under heating and then treated with 0.1 n 2-propanolic HCL-solution (Merck-Art. No. 1.00326) until precipitation of hydrochloride is complete. The precipitate was filtered off and washed with diethylether and dried at room temperature to yield 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride having a melting point of 269-272° C. There is no clear teaching elsewhere in the document of any alternative route or modification to the process which would generate new crystal modifications of 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride or new solvates or hydrates of 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride in different crystal modifications.
Former 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride having a melting point of 269-272° C. was a mixture of amorphous 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride, crystallized 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine hydrochloride and the free base 1-[4-(5-cyanoindol-3-yl)butyl]-4-(2-carbamoyl-benzofuran-5-yl)-piperazine.
Certain crystalline, i.e. morphological forms of pharmaceutical compounds may be of interest to those involved in the development of a suitable dosage form because if the morphological form is not held constant during clinical and stability studies, the exact dosage used or measured may not be comparable from one lot to the next. Once a pharmaceutical compound is produced for use, it is important to recognize the morphological form delivered in each dosage form to assure that the production process use the same form and that the same amount of drug is included in each dosage. Therefore, it is imperative to assure that either a single morphological form or some known combination of morphological forms is present. In addition, certain morphological forms may exhibit enhanced thermodynamic stability and may be more suitable than other morphological forms for inclusion in pharmaceutical formulations.